Everything that was bad about Doom Eternal, multiplied by ten. No new weapons, the new enemies are just boring re-shades of existing models, every fight just feels like an endurance gauntlet.
If fighting a cyberdemon and a marauder at the same time seems like fun to you, then maybe you'll enjoy this. If you enjoyed Doom 2016 but felt like Eternal had lost it's way, give it a miss, because the developers have doubled down on everything you didn't like about eternal. Less creativity, less imagination, less combat variety, more bad level and enemy design, more jumping puzzles and wow, the boss fights are truly woeful.